ADULT, ADULTS, AMBIANCE, ANIMAL, AVES, BARBED, BARN, BARRIER, BARRIERS, BILATERIA, BIRD, BRITAIN, CHORDATA, CHORDATE, COELOMATA, CONCERN, COPULATE, COPULATING, COPULATION, COPULATIONS, COUPLE, COUPLED, COUPLING, COUPLINGS, COVER, DESMETTE, DEUTEROSTOMIA, DEVELOPMENT, ENGLAND, ENUMERATION, EUKARYOTA, EUROPE, EUROPEAN, euteleostomi, FEMALE, FEMALES, FENCE, FENCES, FLAP, FLAPPING, FLAPS, FLIGHT, FLIGHTS, FLUTTER, FLY, FLYING, FREDERIC, FRONT, FULL, GLOBAL, GNATHOSTOMATA, GREAT, HIRUNDINIDAE, HIRUNDO, IN, INDIVIDUAL, INTERCOURSE, INTERCOURSES, IUCN, KINGDOM, LC, LEAST, LENGTH, LIST, LOCOMOTION, LOW, LR, MALE, MALES, MATE, MATERIAL, MATING, MAY, METAZOA, MIGRATORY, MOTION, OBJECT, OF, OPISTHOKONTA, OVERVIEW, OVERVIEWS, PAIR, PARTICULARITY, PASSERIFORMES, PASSERINE, POSE, POSED, POSING, RED, REPRODUCTION, rhipidistia, RISK, RUSTICA, SARCOPTERYGII, SAUROPSID, SAUROPSIDA, SEASON, SEASONS, SETTLING, SETTLINGS, SEXUAL, SHOT, SHOTS, SIGHT, SIGHTS, SPECIES, SPRING, STAGE, SWALLOW, SWALLOWS, TEMPERATE, TETRAPODA, TETRAPODOMORPHA, THREATENED, TO, TRYING, UNION, UNITED, UP, VERTEBRATA, VERTEBRATE, VIEW, VIEWS, WILD, WINGS, WIRE, WIRES, WITH,